editor: drop use of react-monaco-editor

The upstream package is currently broken and doesn't actually save us
any work.

src/fileStorage/actions.ts

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 // Copyright (c) 2022 The Pybricks Authors
 
-import type { monaco } from 'react-monaco-editor';
+import type * as monaco from 'monaco-editor';
 import { createAction } from '../actions';
 import { FileMetadata, UUID } from '.';
 

src/fileStorage/index.ts

@@ -3,7 +3,7 @@
 
 import 'dexie-observable';
 import Dexie, { Table } from 'dexie';
-import type { monaco } from 'react-monaco-editor';
+import type * as monaco from 'monaco-editor';
 
 /** Type to avoid mixing UUID with regular string. */
 export type UUID = string & { _uuidBrand: undefined };